SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11aa2ffbfd9e491f8b26e44eaac47975e10fd64f90bf64e12a1fcee9db3547bd' 
  AND token = 'zNBA8z5vGhRahghCXdWtsmqAgY/HIAdf1sPZG5vhNEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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