SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1c97c843e631a8af7c74213581a30d404591d265951dabf924efbceee5b7a0d' 
  AND token = 'A2eLVmP6l43dr9tQNGUNU+bshBeLAuyttxy3rQRoRd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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