SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50164c264a67ff5e5896f3ed3e9805e54f2723173d6d37d895bd70a3aa1a1f21' 
  AND token = 'G8bV38tDwQpj7HsmvCon/MtqklSL+f7Eg8F1Kh+skt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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