SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb9331b53e09c8234ddda09173b23489cbe3534bc36108c8243632f100675345' 
  AND token = 'WCrGQhUlXZE9Gi94ijKUfWr7CJWExmHB/Iy0LLwCcRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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