SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9e4bedda722a8e2682ed5f597f9478bc6e684190b63f14eed0576710241b6cc' 
  AND token = 'QpeiwvqZZUYMDmJ/jXAg3bOv0KEiHC6AJZ3ijsJ48RY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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