SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '214e28edb08ce2c355b773e2338e779a80de8dd60c3ec6fcfe1fb35d54692a1c' 
  AND token = '6mn9OXuPd3qMC+zmkIfSIYM0wTJyNIAPQFmO4pZ0+24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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