SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10f6663506554b2cab02fcea4b5d420647aaa8b9966cfc47eb4d6631c4160bb3' 
  AND token = 'mqo9XmAiDe0waRyFAxtL3AbVdzdnc3+WQmkEpUp7p2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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