SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4f0acaa3b5a1250d4fe1f42a54ece379a2d70a21bf66bb731981dfc28890589' 
  AND token = 'SBfXrnpVAwu8G9a3XDprCvPuF1YjXteJyqRP7O8IOEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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