SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c606f6cc0ad20f1b254c5aa3601b3f75bc10521112c0b25119ee4fb21199b73c' 
  AND token = 'WjEQqvv3Hvtw3QOOqnrNuNUV/OOzGHPeCYWISnMJVEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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