SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db8b0b703d38f5266abfaf8f232880e02db6b89d641fdcc486e110101f055a55' 
  AND token = '+30A14sCYFRBvqFF3VBNq9w9uQugGpjEB+L4Jp+xTHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}