SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c88da6bf22189569122753d8767baed74ee38c865adb5bafa0c64b8f5746552b' 
  AND token = 'iuSAgFtavmRlQc92Ww2aV+oIkTyqY+14ZTLPoapkUxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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