SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92d1ffcd7f924cac4f3b975857a784f5f4d52d5141699e88544d1aa017b5cf6c' 
  AND token = 'hCqrBLjxAOk+FjYXavvN0eegK7EPNlGexDCSToyq+1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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