SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7d04fc77f495bb8e0d69126eb1631eb1bc1672e02703b133af20d78960dd29a' 
  AND token = 'FMpO+4hHpJebJOB6KUVWph6H/cB1jIkf/s+K0qMDmvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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