SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b26040c9015d892e257fb74f4bbccf7deec81b8026c3f70d4e69e5def9a3c245' 
  AND token = 'TYSZ3WrJJN575EriAUXGdXZwcUGCIV6g5H8sptiRWh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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