SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c499bad5f99cfe233a094fb73292073b3a6695ef18b604ec4d7afed72eef205' 
  AND token = 'rJCNjeYwCavNid7CP8YUkHgsVulW+Nh++umSX4DSAMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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