SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7b2e5e65368baa0251fe40dcdd0ad0dfa4f59b8c38fddafcfba2af9e6d17d34' 
  AND token = '0pKi8U3KExV28UOOAFCyxOifF5RFZFPDYSLfYCMIizc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}