SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b10935193cc6b610b4a603060f5a43f25ef3cde0b0061a4b9b809fc3f587b28' 
  AND token = 'Lw1Su+1w/jOvzlfCedVDaWSaYLzEkAsEeLZ5afgF4Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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