SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75eff1541600855337396ec92dd228b6074927c8ee3721a686cd9424cbf208b0' 
  AND token = 'Ac6jwtA6+VdsRvPJvOr++jPbusL3fITdWA842u4Dw4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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