SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35c5c2e7abd04bd18e51463f15230437dfc411b4b304bf0a7b98f8190ac35252' 
  AND token = 'R5NwMCgjtzL1jNhU96og6gdZiP2snJ5//eUbmQH8bfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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