SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1479cbc88515820cf4465654e14cb676d651f391b81774b9d0dd13a1cc6c3e35' 
  AND token = 'egFtVxeaTfz1qPhAxo3sHNPBYsiXKGBqFonN5uYlr6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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