SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '459cd96029172c7511ca48d9a227b5e8ffbea54a271cca7a887b7f593fa75414' 
  AND token = '1YMTsJGJz3unxH7XwKQz0e3mpS/Ri3OwdbN3Fq5beSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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