SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebf748943ff1ee08da8825c86e76a0c87905ff63dcdbcad7c9a5b21c66e18901' 
  AND token = 'FXDoV0D2C5VvmPTtSznJQj4LiBFUKpDaKiqhCpTghoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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