SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d5e4734e1cd998854809f075812c477ba3880281187443f753614b9b03e33a3' 
  AND token = 'IKdWYRESEgHb0R3LXV8DQ08SzxspqaU3ilO9gzpwRu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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