SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3984bd81b149e75fa5b65d1059895ca400ed89b1f31e0395c8f863ae10d49f3' 
  AND token = 'QzKK0+dxGGQ7rmv6HC64QBTMjKB2CSgmm0ZhMctwuqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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