SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac8d375203d7c605fdad5357066a837b176589a826658c5bffbd3b1239177c9' 
  AND token = 'KTaCrV4/dshdQWaEEtaTbsL2zY6qZlgpze+3rRDU6D4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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