SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '436ef52f5ff1fccdca0ddefaaddb75f6fccba3bd423e6152e6ca86558afc2d5c' 
  AND token = 'rWxyzvBRhToyKtw9q6GEVLGp6kl1SwkDrFE24xSKlz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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