SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '496b6ed874ca1102eb45d705e1009bbdc63e82ebb5160beaf2c4251bdf5daffc' 
  AND token = 'Pux1Hymq4b4cKoCNiZzrv1DIGmK/JYjWeAGSxh1r4Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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