SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a60219601904cbecd0a703902338dcd18b27d1ed0b7d62f047b141294a0a467' 
  AND token = 'g39m47zisYk2yeZuzKlfLPQl0W55GocA/VSARzCIETk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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