SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8322d798c86732ebb4469283988b5103f5512d10f08dc3967d1532a483612252' 
  AND token = 'uPXp3YjXG5uf4gIFrg7LLNSw333G9UlBUudbYt0pfts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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