SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f282bac46d4a2930e32682fa61ac4f6afa987f1df61832893762d143ecc1d74d' 
  AND token = 'GmmBuceex7btb2W+qynoki1CpjQL5tBNYirq0XbttSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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