SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d9cc76a3df6fcb7842760ae31a885d6cce73f0ae93c980740d86a8c8d5fd53a' 
  AND token = '7YV3m7HCrSCzCPjQBVRXXIQhQu30XXrVkYOxhq8xelM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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