SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ed70728803a03473b63b26513ac3627992fb729f584ffda6c75680ff95207be' 
  AND token = 'UtU8e7ufxYYZ4bMAe9tkJLU9Hb1LdTcigp6U9dJhTm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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