SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a545107d89a0f1fea3765cc2f84a060e207947b3d4fbda1ca39f23050fb04242' 
  AND token = 'knqPGBpX2faK81LbZBqBHRANpbDHwiWJmx6SjFBWRT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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