SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4de5de0ddb7ab969ab5ca39deedacfd2115242bd1893bfbe987980a1a3291738' 
  AND token = 'lLhsq/+zolFWxNLtaiMSmAKNzySU4ADgFcdU2mVeSYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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