SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f4172bba8a243fb1b78ecb13358b3cd9b3be0b5e6d612856118ccf92b8f4069' 
  AND token = 'EYYGSsRj+hyVEcmM08YBeXHoV9qzGkulYlAvGkQKpNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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