SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ab31f518b64018008b9095a989bdd8a805e68f401e12a0e3eac71cba26a0a9' 
  AND token = 'GF6/ZCsJQ8k2WOgnP19rns73jZRfVxa2he6+4qbcNIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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