SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bff6033252f079dcd1b819e9370f177acb360807bca0c07cb2653d5cd87844fd' 
  AND token = 'MMOEPmoPmBiOCcp32d3ddxCgCpefG2poFPwzPoOtQM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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