SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d6d0e8940f8d0f0802dc4f66ca726c29cf660d28bdee39ed3aacf0b190b597' 
  AND token = 'T+0p2Zgsk5Av8LiMYIuAVgHAvqQxw/pKAkRA//hBHR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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