SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f7b518552c837e6e93aa530ec1275e9d2e446d4a726e2988bdc13d33f222ede' 
  AND token = 'efDDaz7aupbwwe47Y1mO75ojaBxLLkotHifwiPRJIqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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