SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '334edbd2c1024425e8a265cca1b6e100f7fbf15c2bdd8b15efdcbee8630fa788' 
  AND token = 'pVww3Qq6SbCZVSMPzqVURmQTrPMF4ZvaOajIVlkpkms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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