SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b48a62dab1205ee721eed98b539cfc2ba5f7fcb9d04910baa75cd7a0ec7bd44' 
  AND token = 'U6G988wpr6LhlZIM1UU+oCLlYegSrIOMMmiCCBzjzkY=' 
  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"
    }
  }
}