SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '875545175ab8bb4fc0b57333247a0e31b71fcea56e692bead1294d475980600e' 
  AND token = 'rl9Lj38ZUk60Su4FwBzeeswTM4MC/cVN3Z2eXXmKsVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}