SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8102a4bcb163f7186c610b5909ae42184eb36b3b5087f583f469ad6bff4c182f' 
  AND token = 'm35znxDtZDitFdtjjqahl51ZYAJF1L6oJwHbOwBftOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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